A composite wood panel can be made by placing the mat to be pressed between the press platens of a press (see U.S. Pat. No. 4,517,147). The press platens are then brought together until they are in a compressing position during an initial compression time interval for compressing the mat. Then steam is fed in through steam orifices in both press platens on the mat during a steam pressing time interval.
The steam pressing step is characterized by a flushing interval in which steam issues from the steam orifices of one press platen and flows through the mat and also into the steam orifices of the other press platen which are temporarily cut off from the source of steam. Then the press platens travel into a final position defined by the mat thickness.
The steam input continues from the steam orifices of both platens for the balance of the steam pressing step during a final pressing of the mat.
Then during a final compression time interval the mat is exposed to the action of a vacuum source connected to at least one of the press platens and its steam orifices to dry the mat. A vacuum source can be connected to the steam-supply system instead of the steam generator.
A process of this type is also the subject of German Patent Document No. 34 30 467 and has proved satisfactory. It leads to composite wood panels of very uniform density over the entire panel cross section and also over the thickness of the panel. On the other hand different applications require composite wood panels with covering layers which have a density which is still greater than has been achieved with such earlier systems.